The present invention, in some embodiments thereof, relates to methods and kits for diagnosing cancer and, more particularly, but not exclusively, to the diagnosis of oral and oral pharyngeal cancer.
Oral cancer such as oral squamous cell carcinoma (OSCC) is a common human malignancy, with an increasing incidence (especially in younger people) and a 5-year mortality rate of approximately 50%, which has not changed significantly in more than 50 years. Treatment results in a relatively high rate of related morbidity, due to frequent significant mutilation and compromised functions. OSCC includes both mobile (oral) and base of tongue cancer lesions. Most often an oral cancer lesion is located at the lateral border of the tongue, while one located at the base of tongue is considered especially lethal. Clinically, it is important to note that the therapeutic modality currently offered to patients is based on traditional stage-predicting indices [based mostly on the classification of malignant tumors (TNM) Criteria] and on histological grading. Unfortunately, these predictors are subjective and relatively unreliable, as often two tumors with identical staging and grading behave in a different manner, and while one responds to therapy, the other is lethal.
Salivary testing is a non-invasive alternative to serum testing, an effective modality for diagnosis oral cancer, as well as for monitoring the post therapy status of the patient. Follow-up of patients who have undergone treatment for OSCC is done routinely and often in order to detect recurrences soon after they occur. The development of salivary diagnostic tools for these patients is pivotal. Home testing kits would further facilitate salivary testing as a diagnostic aid, enabling patients, especially those who live far from treatment centers to self-monitor at home. Further more, salivary markers are of particular importance from a clinical point of view, since there is direct contact between the oral cancer lesion and saliva. Even more so, salivary analysis has been shown to be a useful diagnostic tool for other distant malignancies, such as breast cancer.
Circulatory tumor markers for OSCC were investigated in various studies and showed relatively moderate sensitivity and specificity values with relation to diagnosis, prognosis predicting, or treatment monitoring.
For example, Kurokawa et al. analyzed circulatory carcinoembryonic antigen (CEA), SCC, immunosuppressive acidic protein, and Cyfra concentrations in OSCC patients and found sensitivity and accuracy values of 81% and 77.8%, respectively. When CEA, SCC, and immunosuppressive acidic protein were analyzed alone, the values were 69% and 90.3%, respectively [Kurokawa H, et al. Int J Oral Maxillofac Surg 1993; 22:35-8; Kurokawa H, et al J Oral Maxillofac Surg 1997; 55:964-6].
WO2008/001357 teaches methods and kits for diagnosing cancer by determining a level and/or activity of at least one saliva secreted marker in a saliva sample of the subject wherein an alteration in the marker with respect to an unaffected saliva sample is indicative of the cancer.